Dual-pressure oiling system for turbines



April 22, 1924. 1,490,942

H. F. SCHMIDT DUAL PRESSURE OILING SYSTEM FOR TURBINES Filed Sept. 50.1921 HII'Jchmidf INVENTOR Patented Apr. 22, 1924.

UNITED STATES HENRY F. SCHMIDT, O'F SWARTHMORE, PENNSYLVANIA, ASSIGNOREOWESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OFPENNSYLVANIA.

' DUAL-PRESSURE OILING SYSTEM FOR TURBINES.

Application filed September 30, 1921.

To all whom it may concern:

Be it known that I, HENRY F. SCHMIDT, a citizen of the United States,and a resident of Swarthmore, in the county of Delaware and State ofPennsylvania, have invented a new and useful Improvement inDual-Pressure Oiling Systems for Turbines, of which the following is aspecification.

My invention relates to turbine lubricating systems of the dual-pressuretype, that is to say, wherein relatively low pressure oil is supplied tothe bearings and relatively high pressure oil to the oil relay system,and it has for its object to provide apparatus ofthe characterdesignated which at all times insures an adequate supply of oil to therespective pumps, at the same time insuring the complete circulation ofall oil in the systom.

Figure 1 of the accompanying drawing is a side view, partially insection and partially in elevation, of a steam turbine together withvarious elements of the oiling system all arranged and constructed inaccordance with my invention and Figure 2 is a detail View of amodification of a portion of the apparatus shown in Figure 1.

It has been the usual practice hitherto to supply the bearings of steamturbines with oil in copious quantities but at relatively low pressureand to supply the oil relay system with relatively small quantities ofoil at relatively high pressure. The high pressure oil has sometimesbeen supplied b a. pump of the impeller type mounted directly on theturbine shaft, this pump drawing from the common reservoir. It has beenthe usual practice to locate the oil reservoir at a relatively low pointin order to receive all the returned oil by gravity and it has thereforefrequently happened that the high-pressure impeller pump lost itssuction, cutting off the oil supply to the oil relay system.

According to the present invention, I 10- cate one or more relativelylarge-volume, low-pressure pumps in the bottom of a depressed reservoiror sump, either of these pumps being capable of supplying the entireamount of oil used by the turbine at relatively low pressure. This oilis piped directly to the bearings and is furthermore piped to the intakeof a high-pressure impeller pump mounted on the turbine shaft, thusinsuring a copious oil supply to said Serial No. 504,270.

. other low-pressure pump is automatically energized to supply thesystem.

Referring to the drawing for more detailed understanding of my inventionI show the body pontion of a steam turbine at 10 having bearings 11 and12, a governor 13, and a steam chest 14, all of usual form and requiringnodetailed description inasmuch as they form no part of the presentinvention.

A main oil reservoir or sump 15 is mounted at a lower level than theturbine and receives the oil drainage from the bearings 11 and 12through conduits 16 and 17 and receives the oil drainage from thegoverning relay system through a conduit 18.

Two pumps, preferably of the propeller type, are shown at 19 and 20, thepump 19 being driven, for example, by a motor indicated at 21 and thepump. 20 by a small turbine, shown at 22, although the form of primemover used for these pumps is en tirely a matter of choice, as both maybe steam driven or both may be electrically driven if sodesired. Themotor 21 is under the control of a switch 23 and the turbine 22 underthe control of a. throttle valve 35 hereinafter described. The pumps 19and 20 discharge into a common conduit 24 through suitable check'valves25 and 26 and the conduit 24 branching to the bearings 11 and 12 throughconduits 27 and 28. A further branch 29 leads from the conduit 24 to theintake of an impeller pump 30 mounted on the main turbine shaft andsupplying oil to the oil relay system through a conduit 31. Obviously ahigh-pressure oil pump of any other type may be employed if found desirale.

In the normal operation of the oiling system the pump 19 is employed,the motor 21 being operated by the closure of the switch 23. Under theseconditions, the oil pressure in the conduit 24, for example fi e poundsper square inch, is sufficient to push a piston 32 mounted in a cylinder33 connected to the conduit .24 to the left against a spring 34,

holding the throttle valve 35 in the closed position. The pressure offive pounds per square inch in the conduit system 24, 27, 28, 29 issufficient to thoroughly lubricate the main bearings and furthermoreinsure a copious supply of oil at the intake of the pump 30 from whenceoil is delivered to the relay system at, for example, seventy-fivepounds per square inch.

Upon a decrease in the pressure in the conduit 24 below a predeterminedamount, for example five pounds per square inch, from any cause, as bythe burning out of the motor 21 or the failure of the current sup-ply,the check valve 25 closes, preventing the backflow of oil and thedecreased pressure in the conduit 24 permits the piston 32 to move tothe right under the influence of the spring 34:, opening the throttle 35and energizing the small turbine 22, whereupon the pum 20 starts intooperation, opening the chec valve 26 and supplying oil as desired to theconduit 24. If desired, an alarm may be sounded as the blowing of asteam whistle 36 connected to the turbine supply line below the throttlevalve.

In the arrangement shown in Fig. 2, a

. reservoir 37 is mounted above the intake of the pump 30 and connectedthereto and receives oil from the conduit 29, any excess being returnedto the conduit 17 through an overflow conduit 38. Thus a copious supplyof oil is assured for the .pump 30.

It will be observed that by the use of the foregoing structure the sump15 may be located at any desired low position, even at some considerabledistance from the turbine. The location of the pumps 19 and: 20 near thebottom thereof insures an adequate supply of oil even if but arelatively small amount of oil remains in the sump. Furthermore, itisnot necessary that suction be relied uon to any extent in supplying oilto the hlgh-pressure pump 30, and thus an adequate supply ofhigh-pressure oil is at all times insured asis necessary for the properfunctioning of the governing system.

While I have shown my invention in but one form, it will be obvious tothose skilled in the art that it is not so limited,-but is susceptibleof various other 0 anges and modifications, without departing from thespirit thereof, and I desire, therefore, that only such limitationsshall be placed thereupon as are imposed by the prior art or as arespecifically set forth in the appended claims.

What I'claim is 1. In a duaLpressure oiling system, thev combinationwith bearings to be lubricated, an oil reservoir, and a primary pumpoperating therefrom and supplying a relatively large amount of oil at adesired pressure to the bearings, of a secondary pumpsupplied from saidprimary pump and oppressure pump erable to supply a relatively smallamount of oil at a higher desired ressure.

2. In a dual-pressure oiling system, the combination with an oilreservoir, of two primary pumps operable therefrom to supply arelatively large amount of oil at the lower desired pressure, one ofsaid pumps normally operating to supply said pressure and means forenergizing the other of said pumps when said pressure falls below apredetermined minimum amount, and a secondary pump supplied from saidlowpressure supply and operable to sup-pl a relatively small amount ofoil at the big er desired pressure.

3. In a dual-pressure turbine oiling system, the combination with an oilreservoir located to receive all oil drainage from said turbine bygravity, a low-pressure pump operable in said reservoir to supply oil tothe bearings of said turbine, and a highsupplied from said lowpressurepump and adapted to supply relatively high-pressure oil to the oil relaysystem.

4. In a dual-pressure turbine oiling system, the combination with an oilreservoir located to receive all oil drainage from said turbine bygravity, an independently driven low-pressure oil pump operable in saidreservoir and connected to supply the turbine bearingsdirectly withlow-pressure oil, and a high-pressure pu-mp mounted directly upon saidturbine shaft said low-pressure pump, pump being connected to supply oilto oil-relay system of said turbine.

5. In adual-pressure turbine oiling system, the combination with an oilreservoir located to receive all oil drainage from said turbine bygravity, two independentlydriven low-pressure pumps operable in saidreservoir to supply oil to a low-pressure piping system, one of saidpumps normally operating to supply said pressure and means forautomatically energizing the other of said pumps upon a decrease in thepressure in said system below a predetermined amount, and ahigh-pressure pump supplied from said low-pressure system and operableto supply oil to the high-pressure piping system of the turbine.

6. In a dual-pressure turbine oiling system, the combination with an oilreservoir located. to receive all oil drainage from said turbine bygravity, two independentlydriven low-pressure pumps operable in saldsaid high-pressure the reservoir to supply oil to alow-pressure pipingsystem, one of said pumps normally operating to supply said pressure andmeans for automatically energizing the other of said pumps upon adecrease in the pressure in said system below a predetermined amount,and a high-pressure pumpmounted upon the turbine shaft and supplied fromand supplied from said low-pressure system and operable to supply oil tothe high-pressure piping system of the turbine.

7. In a dual-pressure turbine oiling system the combination with an oilreservoir located to receive all oil drainage from said turbine bygravity, an independently driven low-pressure oil pump operable in saidreservolr and connected to supply the turbine bearings directly withlow-pressure oil, and an impeller pump adapted to supply relatively highpressure oil, mounted directly on the turbine shaft and supplied fromsaid low-pressure pump, said high-pressure pump being connected tosupply oil to the highpressure oil piping system of said turbine.

8. The method of insuring an adequate oil supply to a high-pressureimpeller oil pump mounted on the shaft of a steam turbine having alow-pressure bearing oiling system which comprises supplying oil fromsaid low-pressure system to the intake of said pump.

9. The method of circulating oil in a dualpressure turbine lubricatingsystem which comprises collecting oil in a depressed sump, pumping theentire oil supply therefrom at relatively low pressure and passing aportion of the oil so supplied through an additional pump for theimparting of a relatively high pressure thereto.

In testimony whereof, I have hereunto subscribed my name this 22nd dayof September, 1921.

HENRY F. SCHMIDT.

